Numerical classification and identification of Bacillus sphaericus including some strains pathogenic for mosquito larvae

Abstract

Ninety-one strains of Baciffus sphaericus, including representatives of all the established DNA homology group, related round-spored and oval-spored species, and six strains pathogenic for mosquito larvae, were examined for 155 characters. Numerical analyses (Jaccard coefficient/average linkage clustering) based on the 88 variable features revealed 14 clusters at the 79 yo similarity level that contained more than one strain and 17 single member clusters. All insect pathogenic strains were recovered in a single cluster and the classification was in accord with an established classification based on DNA sequence homology. Two frequency matrices for probabilistic identification were constructed and tested. A comprehensive matrix comprising 14 mesophilic, round-spored taxa and 27 tests gave good results for identification of hypothetical median organisms, cluster overlap and identifications of representative strains (based on data generated in the classification study). Reference strains for the 14 taxa and eight additional insect pathogenic strains were examined for the 27 tests and were correctly identified with high scores using this matrix. A second matrix comprising seven taxa and 13 tests also performed well in the theoretical evaluation and correctly identified the reference strains and insect pathogenic strains.

Differentiation of mosquito-pathogenic strains of Bacillus sphaericus from non-toxic varieties by ribosomal RNA gene restriction patterns

“…These groups have since been validated by numerical classification of phenotypic features (Alexander & Priest, 1990) and enzyme electrophoretic patterns (Singer, 1988). It would seem that these groups represent species, although formal descriptions have not been published.…”

Biological activity of Bacillus spp. evaluated on eggs and larvae of red palm weevil Rhynchophorus ferrugineus

“…These two species, formerly assigned to Bacillus, have been recently transferred to the new genus Lysinibacillus (Ahmed et al 2007). L. sphaericus is commonly used in the biological control of various families of insects (Alexander and Priest 1990;Woodburn et al 1995;Rippere et al 1997;Salama et al 2004).…”

Distribution of restriction endonucleases among some entomopathogenic strains of Bacillus sphaericus

“…These strains serve as useful intermediate hosts for the generation of fully modified DNA. Bacillus sphaericus is a poorly classified species containing at least eight species-ranked taxa and probably many more (Krych et al 1980 ;Alexander and Priest 1990). It is therefore…”

“…Bacteria were grown at 30°C incorporation of novel toxin genes (Porter et al 1993), and until early stationary phase (16 h) in 25 ml of nutrient broth second, resistance to the major, crystal toxin is increasingly and harvested by centrifugation. Cells (70 mg wet weight) being reported (Nielsen-Leroux et al 1995 ;Rodcharoen and were washed in phosphate buffer (50 mmol l −1 , pH 7·5) and Mulla 1996) and could be retarded by presentation of toxin resuspended in 200 ml of 25% sucrose in 50 mmol l −1 Triscombinations to target insects.…”